Bastian Bloessl
100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
/*
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* Copyright (C) 2015 Bastian Bloessl <bloessl@ccs-labs.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "sta.h"
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#include <cstring>
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#include <iostream>
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using namespace gr::ieee802_11::equalizer;
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void sta::equalize(gr_complex* in,
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int n,
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gr_complex* symbols,
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uint8_t* bits,
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std::shared_ptr<gr::digital::constellation> mod)
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{
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if (n == 0) {
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std::memcpy(d_H, in, 64 * sizeof(gr_complex));
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} else if (n == 1) {
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double signal = 0;
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double noise = 0;
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for (int i = 0; i < 64; i++) {
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if ((i == 32) || (i < 6) || (i > 58)) {
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continue;
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}
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noise += std::pow(std::abs(d_H[i] - in[i]), 2);
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signal += std::pow(std::abs(d_H[i] + in[i]), 2);
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d_H[i] += in[i];
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d_H[i] /= LONG[i] * gr_complex(2, 0);
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}
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d_snr = 10 * std::log10(signal / noise / 2);
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} else {
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gr_complex H_update[64];
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gr_complex H[64];
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gr_complex p = POLARITY[(n - 2) % 127];
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H[11] = in[11] * p;
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H[25] = in[25] * p;
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H[39] = in[39] * p;
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H[53] = in[53] * -p;
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int c = 0;
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for (int i = 0; i < 64; i++) {
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if ((i == 11) || (i == 25) || (i == 32) || (i == 39) || (i == 53) ||
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(i < 6) || (i > 58)) {
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continue;
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} else {
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symbols[c] = in[i] / d_H[i];
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bits[c] = mod->decision_maker(&symbols[c]);
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gr_complex point;
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mod->map_to_points(bits[c], &point);
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H[i] = in[i] / point;
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c++;
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}
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}
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for (int i = 0; i < 64; i++) {
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int n = 0;
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gr_complex s = 0;
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for (int k = i - beta; k <= i + beta; k++) {
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if ((k == 32) || (k < 6) || (k > 58)) {
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continue;
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}
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n++;
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s += H[k];
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}
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H_update[i] = s / gr_complex(n, 0);
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}
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for (int i = 0; i < 64; i++) {
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if ((i < 6) || (i > 58)) {
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continue;
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}
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d_H[i] =
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gr_complex(1 - alpha, 0) * d_H[i] + gr_complex(alpha, 0) * H_update[i];
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}
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}
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}
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double sta::get_snr() { return d_snr; }
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